The outbreak of H5N9 avian influenza occurred at a California duck farm in November 2024. Also, new research pinpoints 298 parts of the genome associated with higher risk of bipolar disorder. This could lead to better treatments.

This week, the World Organization for Animal Health reported that it had been notified by the USDA that a November outbreak of highly pathogenic avian influenza on a California duck farm was caused by a strain not before seen in the United States: H5N9. The dominant bird flu strain circulating currently, H5N1, has led to massive culling of bird flocks, has infected dairy cattle, and has killed almost 500 people around the world since 2003. The US reported its first human death from bird flu earlier this month.

Experts stressed that the new strain did not itself appear to be an immediate human threat. But the rise of a new strain is troubling and points to the risk of a viral phenomenon known as “reassortment,” in which different viruses mingled in a host can sometimes exchange bits of viral code, forming new strains.

SciFri’s Charles Bergquist joins Flora Lichtman to talk about H5N9 and other stories from the week in science, including a spacewalk that was meant to include a search for microbes on the outside of the International Space Station, a possible positive side effect of scratching an itch, and the discovery of 66 million-year-old fossilized vomit.

Bipolar disorder is one of the most common mental illnesses—it affects an estimated 40 million people worldwide, about 2.8% of the population. Bipolar disorder can cause extreme mood swings, and be debilitating without treatment.

In an effort to untangle the mysteries of where bipolar disorder originates, researchers studied the genomes of more than 40,000 people with the condition. When comparing these genomes to those of people without bipolar disorder, the researchers were able to pinpoint 298 different parts of the genome associated with the mental illness. With this better understanding of the genome, better, more targeted treatments for bipolar disorder may be possible.

Joining Flora to talk about this research is Dr. Niamh Mullins, assistant professor of psychiatric genomics at the Icahn School of Medicine at Mount Sinai in New York.

Transcripts for each segment will be available after the show airs on sciencefriday.com.

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